A Japanese patent application published under No. Sho 63-185777 purports to describe a folding apparatus for a rotary printing press comprising a shaft which is turnable by means of a hand crank being attachable thereto, and on which there are arranged several couplings. By disengaging one of the couplings and operating the hand crank, the phase position of a control cam can be adjusted. After the adjustment is performed, the coupling is engaged again. With this device, the collection of products is carried out by a separate collecting cylinder which does not simultaneously carry out a cutting function.
Another folding apparatus is purportedly described in German patent application DE 38 28 372 A1. This device contains a collecting cylinder for the transport of at least two signatures. This collecting cylinder includes multiple operating devices, said operating devices, at their respective ends opposite two control cams, being respectively provided with two sensing rolls arranged side by side on a common axis. Between the two control cams, which are stationary with respect to the collecting cylinder, there is arranged a carrier supporting multiple lugs which can be brought into an active and into a passive position. In the active position, the lugs prevent a folding operation from being carried out by bracing themselves against one of the two sensing rolls of each operating device. When the lugs are in a passive position, then the sensing rolls can follow the slopes of the respective control cam and trigger folding and pin-on operations. This complicated construction, as is apparent from the figures of DE 38 28 372 A1, is only justified in large printing and gravure printing presses with as much as eight etchings on the surface of a printing unit cylinder. In the smaller folding apparatuses this mechanical input is too costly and therefore not justified.
U.S. Pat. No. 3,865,361 purports to disclose a folding cylinder with a cam at its front side. This cam is provided with several roll-off surfaces from which rolls may roll off in such a way as to be arranged side by side, thereby moving pin shafts accordingly. Conversion of the folding cylinder from the "collect" mode to the "non-collect" mode takes place through axial displacement of the cam at the common high point of the roll-off surfaces. When a construction supporting a cam is axially displaceable, the danger that play will occur during operation increases, resulting in the likelihood that the construction will swing. This makes the use of a displaceable cam problematic. Also, concerns for manufacturing costs make cams with multiple roll-off surfaces undesirable because of the additional hardening processes required for the different surfaces.
Finally, the disclosure in German Patent, No. DE 17 61 134 purportedly teaches a folding device for rotary printing presses which is convertible from a "collect" mode to a "non-collect" mode and has a controlled folding cylinder. This configuration contains a control disk with a loop-type cam groove being formed therein and with multiple diametrically opposed, inwardly oriented protrusions being arranged within said cam groove. Further, the device provides shiftable gear wheels for regulating the rotational speed of the control disk with respect to the rotational speed of the folding cylinder. The major disadvantage of this folding device is the space-consuming dimension of the shiftable gearing with its large number of straight-tooth gear wheels. In addition to the space consumption, this configuration also has a negative effect on manufacturing costs.